package basic_1016;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		Scanner scanner=new Scanner(System.in);
		int C1=scanner.nextInt();
		int C2=scanner.nextInt();
		
		scanner.close();
		int deltaC=C2-C1+50;
		int time=deltaC/100;
		
		int s=time%60;
		time=time/60;
		int m=time%60;
		int h=time/60;
		
		String ss=s<10?"0"+s:""+s;
		String mm=m<10?"0"+m:""+m;
		String hh=h<10?"0"+h:""+h;
		
		System.out.println(hh+":"+mm+":"+ss);
	}
	
}
